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Effects of early weaning on the circadian rhythm and behavioral satiety sequence in rats
Lisiane dos Santos Oliveira1, Ligia Pereira da Silva, Aline Isabel da Silva
1Centro Acadêmico de Vitória - Universidade Federal de Pernambuco, Vitória de Santo Antão - PE, Brazil. lisianenutricao@yahoo.com.br
Insights
Early weaning in rats delayed satiety and altered feeding patterns, impacting circadian rhythms. These early life changes may influence long-term feeding behavior and homeostasis.
Area of Science:
- Animal Behavior
- Chronobiology
- Developmental Biology
Background:
- Early life experiences, such as weaning age, can have lasting effects on physiological and behavioral outcomes.
- Understanding the impact of early weaning on feeding behavior and circadian rhythms is crucial for comprehending long-term health implications.
Purpose of the Study:
- To investigate the long-term effects of early weaning on the circadian rhythm of food intake and behavioral satiety sequence in adult rats.
- To determine if different early weaning ages (15, 21, or 30 days) result in distinct alterations in feeding behavior.
Main Methods:
- Wistar rat pups were weaned at postnatal days 15 (D15), 21 (D21), and 30 (D30).
- Body weight and food intake were monitored until 150 days of age.
- Circadian rhythm of food intake was assessed at 90 days, and behavioral satiety was evaluated at 35 and 100 days.
Main Results:
- While body weight and overall food intake were not significantly altered by weaning age, the D15 group exhibited delayed satiety at 100 days compared to the D30 group.
- Early weaning at D15 led to changes in food intake patterns during both light and dark phases of the circadian cycle.
- Behavioral satiety was significantly delayed in rats weaned at day 15.
Conclusions:
- Early weaning, particularly at day 15, can disrupt feeding behavior, affecting satiety and circadian rhythms in adult rats.
- Environmental stimuli during early weaning may contribute to hyperphagia and dysregulation of homeostasis.
- This study supports the concept that early-life adversity can be a determinant of chronic diseases.
Abstract:
The objective of this work was to study the effect of early weaning on circadian rhythm and the behavioral satiety sequence in adult rats. Male Wistar rat pups were weaned for separation from the mother at 15 (D15), 21 (D21) and 30 (D30) days old. Body weight and food intake was measured every 30 days until pups were 150 days old. At 90 days of age, the circadian rhythm of food intake was evaluated every 4h for three days. Behavioral satiety was evaluated at 35 and 100 days of age. This work demonstrated that body weight and food intake were not altered, but the behavioral satiety sequence demonstrated that the D15 group delayed satiety compared with the D30 group at 100 days of age. In the circadian rhythm of the food intake study, early weaning (D15) changed food intake in the intermediary period of the light phase and in the intermediary period of the dark phase. In conclusion, our study showed that early weaning may alter the feeding behavior mainly in relation to satiety and the circadian rhythm of feeding. It is possible that the presence of other environmental stimuli during early weaning can cause hyperphagia and deregulate the mechanisms of homeostasis and body weight control. This study supports theories that depict insults during early life as determinants of chronic diseases.
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